Wear-resistant stainless steel pipe for pneumatic cylinder barrel and preparation process of wear-resistant stainless steel pipe

Abstract

The invention relates to the technical field of stainless steel pneumatic cylinder barrels, and particularly discloses a wear-resistant stainless steel pipe for a pneumatic cylinder barrel and a preparation process thereof.The wear-resistant stainless steel pipe for the pneumatic cylinder barrel comprises the steps that firstly, a powder metallurgy method is adopted, tungsten carbide, cerium oxide, chromium nitride and other components are added into stainless steel powder, and the performance of a steel pipe base body is enhanced; the corrosion-resistant alloy layer is deposited on the surface of the steel pipe, so that the corrosion resistance, wear resistance and other properties of the steel pipe are enhanced, finally, a silicon nitride wear-resistant ceramic layer is sintered on the surface of the corrosion-resistant coating, and two lubricants of graphite and molybdenum sulfide are synthesized in gaps and holes of the wear-resistant ceramic layer. The defects on the ceramic surface are blocked; and the ceramic coating is endowed with a self-lubricating function.

Description

Technical Field

[0001] The present invention relates to the technical field of stainless steel pneumatic cylinder barrels, and particularly to a wear-resistant stainless steel pipe for a pneumatic cylinder barrel and a preparation process thereof. Background Art

[0002] A pneumatic actuator is a mechanical driving device powered by compressed air and is widely used in fields such as automation, industrial machinery, instrument valves, etc. A pneumatic cylinder barrel is one of the components of its core component - the air cylinder. Inside the pneumatic cylinder barrel, air pushes the piston or blade to move during the compression - release cycle process, realizing the output of mechanical energy.

[0003] Since the pressure inside the air cylinder constantly changes cyclically during the operation of the actuator, and the gas inside the air cylinder is generally inhaled from the external environment, therefore, under complex and harsh working conditions, the pneumatic cylinder barrel interacts with dust particles in the air and other substances to cause wear, or inhales acidic gases in the environment, resulting in corrosion of the cylinder barrel, and further leading to problems such as poor sealing of the cylinder barrel and air leakage of the air cylinder, seriously affecting the production progress and production safety. Therefore, enhancing the wear resistance and corrosion resistance of the pneumatic cylinder barrel, increasing the service life of the pneumatic cylinder barrel during continuous operation, and reducing the replacement frequency of the pneumatic cylinder barrel are particularly important for the development of the pneumatic cylinder barrel. Summary of the Invention

[0004] The purpose of the present invention is to provide a wear-resistant stainless steel pipe for a pneumatic cylinder barrel and a preparation process thereof, to enhance the wear resistance and corrosion resistance of the pneumatic cylinder barrel, and to solve the problems that the cylinder barrel is prone to wear or corrosion under complex and harsh working conditions, resulting in poor sealing of the cylinder barrel and air leakage of the air cylinder.

[0005] To solve the above technical problems, the present invention provides the following technical solutions: A preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel, specifically as follows: Step 1: After uniformly ball-milling the stainless steel powder and the reinforcing phase, put them into a cylinder barrel mold and press and shape them under a pressure of 700 - 800 MPa. Subsequently, under nitrogen protection, heat them to 1350 - 1400 °C and sinter for 1 - 3 h. After sintering is completed, through heat treatment and tempering processes, obtain a cylinder barrel steel pipe; Step 2: After grinding the cylinder barrel steel pipe flat, wash it with absolute ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to sequentially deposit a bottom layer, a transition layer, and an alloy layer on the surface of the cylinder barrel steel pipe to obtain a corrosion-resistant steel pipe; Step 3: Disperse polysilazane, silicon nitride, and ytterbium oxide into xylene to form a dispersion liquid. Subsequently, spray the dispersion liquid onto the corrosion-resistant steel pipe. After spraying is completed, heat it to 50 - 70 °C to completely volatilize the xylene, and then sinter it at 1250 - 1300 °C for 3 - 5 h under nitrogen protection. After sintering is completed, cool it to room temperature to obtain a ceramic-coated steel pipe; Step 4: Dissolve D-glucose, sodium molybdate and thiourea in deionized water to form a lubricating coating solution. Finally, immerse the ceramic-coated steel pipe into the lubricating coating solution and ultrasonically treat it for 10 - 20 min. After impregnation, react the ceramic-coated steel pipe together with the lubricating coating solution at 270 - 300 °C and 10 - 15 MPa for 24 h to obtain a wear-resistant stainless steel pipe for pneumatic cylinder barrels.

[0006] As a limitation of the present invention, in Step 1, the reinforcing phase is composed of cerium oxide, chromium nitride, copper powder, cobalt powder, boron iron powder and tungsten carbide; in the cylinder barrel steel pipe, the mass fraction of cerium oxide is 0.05% - 0.3%, the mass fraction of chromium nitride is 3.4% - 3.8%, the mass fraction of copper powder is 3% - 5%, the mass fraction of cobalt powder is 2% - 4%, the mass fraction of boron iron powder is 0.8% - 1.2%, the mass fraction of tungsten carbide is 6% - 8%, and the balance is stainless steel powder.

[0007] As a limitation of the present invention, in Step 1, the heat treatment and tempering processes are specifically as follows: Mix alumina and ammonium chloride in a mass ratio of (93 - 97):(3 - 7) and cover the surface of the fired product with a thickness of 5 - 10 mm. Keep it at 1100 - 1150 °C for 4 h. After the heat preservation is completed, cool it to room temperature and temper it at 250 - 300 °C for 3 - 5 h to obtain the cylinder barrel steel pipe.

[0008] Using the mixed powder of alumina and ammonium chloride is helpful for the heat treatment of stainless steel. The alumina powder is inert, and ammonium chloride decomposes upon heating to produce a reducing atmosphere. Covering the surface of stainless steel can isolate air to prevent stainless steel from oxidation and decarburization. At the same time, the alumina powder has good thermal conductivity, which helps the stainless steel pipe to be heated evenly. In addition, using the mixed powder can also avoid deformation or adhesion of stainless steel pipe parts during the treatment process.

[0009] As a limitation of the present invention, in Step 2, the thickness of the bottom layer is 0.1 - 0.3 μm, the thickness of the transition layer is 0.05 - 0.1 μm, and the thickness of the alloy layer is 0.18 - 0.28 μm.

[0010] As a limitation of the present invention, in Step 2, the specific process of magnetron sputtering is as follows: First, turn on the power supply and start the vacuum pump to pump the vacuum to 1.2×10 -3 -1.5×10 -3First, heat the cylinder steel pipe to 380 - 400 °C at a heating rate of 6 - 10 °C / min, then start the heater. Introduce argon into the magnetron sputtering device with a flow rate of 70 - 80 sccm, set the bias voltage to (-60) - (-80) V, and perform bias etching for 10 - 20 min. After the etching is completed, turn on the chromium target power supply to deposit a bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the deposition of the bottom layer is completed, introduce nitrogen to deposit a transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the titanium-aluminum-vanadium alloy target power supply to deposit an alloy layer on the surface of the transition layer.

[0011] First, deposit a chromium layer on the steel pipe as a bottom layer that tightly adheres to the steel pipe substrate. Then, introduce nitrogen to deposit chromium nitride on the bottom layer as a transition between the bottom layer and the alloy layer, reducing the defect density while relieving the internal stress of the coating. Finally, deposit a corrosion-resistant alloy layer on the transition layer to enhance the hardness and corrosion resistance of the steel pipe.

[0012] As a limitation of the present invention, during magnetron sputtering, the argon flow rate is 30 - 40 sccm, the sputtering pressure is 0.4 - 0.5 Pa, the chromium target power is 180 - 200 W, and the sputtering deposition time of the bottom layer is 10 - 15 min; the nitrogen flow rate is 10 - 20 sccm, and the sputtering deposition time of the transition layer is 5 - 10 min; the titanium-aluminum-vanadium alloy target power is 150 - 180 W, and the sputtering deposition time of the alloy layer is 2 - 3 h.

[0013] As a limitation of the present invention, in step 2, heat treatment is performed after magnetron sputtering, specifically: After the deposition is completed, heat it to 280 - 300 °C at a heating rate of 10 - 15 °C / min, then hold for 5 - 6 h and cool. Perform the heat treatment process of cyclic heating - holding - cooling 3 - 5 times to obtain the corrosion-resistant steel pipe.

[0014] Through cyclic heat treatment, atomic rearrangement is promoted, crystallization is induced, defects in the coating are reduced, residual stress in the coating is released, the formation of brittle compounds (such as titanium-aluminum metal compounds) is inhibited, atomic mutual diffusion at the interface is promoted, the adhesion ability of the coating is increased, and grain coarsening and interface reaction caused by single high temperature can also be avoided.

[0015] As a limitation of the present invention, in step 3, the mass ratio of polysilazane, silicon nitride powder, and ytterbium oxide powder is (8 - 12):(4 - 6):(1 - 2); the viscosity of the dispersion liquid is 8 - 12 Pa·s.

[0016] As a limitation of the present invention, in step 4, the mass ratio of D-glucose, sodium molybdate, thiourea, and deionized water is (50 - 60):(8 - 10):(10 - 15):(180 - 220).

[0017] A wear-resistant stainless steel pipe for a pneumatic cylinder barrel, which is processed by the above-mentioned preparation process.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention first adopts the powder metallurgy method. During the metallurgy process, a reinforcing phase composed of cerium oxide, chromium nitride, copper powder, cobalt powder, boron iron powder and tungsten carbide is added to the stainless steel powder. Among them, the addition of cerium oxide can refine the grains, purify impurities such as sulfur and oxygen in the stainless steel, reduce the brittleness of the grain boundaries, and improve the strength and toughness of the steel pipe; chromium nitride is dispersed in the stainless steel matrix to promote the formation of the chromium oxide passivation film, improve the hardness, wear resistance and corrosion resistance of the steel pipe, and can also delay the formation of the iron-chromium brittle phase at high temperatures, improving the high-temperature stability of the steel pipe; the addition of copper powder can promote sintering densification; cobalt powder, as a binder phase, enhances the interfacial bonding ability between the stainless steel powder and other powders, and can also improve the red hardness of the stainless steel and maintain the hardness at high temperatures; boron iron powder is used to reduce the sintering temperature and improve the hardenability of the stainless steel, and tungsten carbide can significantly improve the wear resistance and high-temperature stability of the steel pipe; the performance of the stainless steel pipe is enhanced through appropriate ratios.

[0019] The present invention adopts the magnetron sputtering method. First, a chromium layer with good compatibility with the steel pipe matrix is deposited on the surface of the steel pipe as a bottom layer, then nitrogen is introduced to deposit a chromium nitride layer on the surface of the bottom layer as a transition layer, and then a titanium-aluminum-vanadium alloy target is added to deposit a corrosion-resistant alloy layer on the surface of the transition layer. Titanium-aluminum-vanadium can form a hard phase on the surface of the matrix during deposition, enhancing the wear resistance and corrosion resistance of the steel pipe.

[0020] The present invention uses polysilazane as the ceramic binder phase, silicon nitride as the ceramic phase, and ytterbium oxide as the sintering-promoting phase. After dispersing them in xylene, they are sprayed on the surface of the steel pipe. After high-temperature sintering, a ceramic coating with good wear resistance, corrosion resistance and high-temperature resistance is formed on the surface of the steel pipe. Then, three lubricant phase precursors of D-glucose, sodium molybdate and thiourea are introduced, and two lubricant phases of graphite and molybdenum disulfide are in-situ synthesized in the defect pores of the ceramic coating, assisting the lubrication and friction reduction during the friction process of the ceramic coating, filling the ceramic defects, and further enhancing the wear resistance of the ceramic. Detailed implementation manners

[0021] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] Stainless steel powder (316L stainless steel, particle size: 100 mesh, Cr: 16.8%, Ni: 10.7%, Mo: 2.1%, C: 0.02%, Fe: ≥69.1%), cerium oxide (particle size: 200 mesh), chromium nitride (particle size: 120 mesh), copper powder (particle size: 200 mesh), cobalt powder (particle size: 200 mesh), ferroboron powder (boron content: 18%, particle size: 200 mesh), tungsten carbide (particle size: 120 mesh), chromium target (purity: ≥99.9%), titanium-aluminum-vanadium alloy target (aluminum: 6.0%, vanadium: 4.0, others: 0.66, the balance is titanium), polysilazane (poly-1,1-dimethylsilazane, Mn: 600 - 800), silicon nitride powder (particle size: 200 mesh), ytterbium oxide powder (particle size: 200 mesh).

[0023] Example 1: A preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel, specifically as follows: Step 1: By mass fraction, mix 80.9% of stainless steel powder, 0.1% of cerium oxide, 4% of chromium nitride, 4% of copper powder, 3% of cobalt powder, 1% of ferroboron powder, and 7% of tungsten carbide. Use a planetary ball mill to ball mill for 20 min to make it evenly mixed. Then put it into a cylinder barrel mold and press and shape it under a pressure of 750 MPa. After that, put it into a tube furnace and sinter at 1350 - 1400 °C for 2 h under the condition of nitrogen as the protective gas. After sintering, transfer it to a vacuum heat treatment furnace and form a 10 mm thick covering layer on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. Keep it at 1100 °C for 4 h. After heat preservation, cool it to room temperature and temper at 250 °C for 4 h to obtain a cylinder barrel steel pipe; Step 2: After grinding the cylinder barrel steel pipe smoothly, wash it with anhydrous ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder barrel steel pipe in sequence. The process is as follows: First, turn on the power supply and start the vacuum pump to pump the vacuum to 1.5×10 -3Pa. Subsequently, start the heater and heat the cylinder steel pipe to 400 °C at a heating rate of 10 °C / min. Introduce argon into the magnetron sputtering device with a flow rate of 70 sccm. Set the bias voltage to -80 V and perform bias etching for 15 min to remove the oxide layer and contaminants on the surface of the cylinder. After the etching is completed, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit a bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the deposition of the bottom layer is completed, keep other parameters unchanged, introduce nitrogen with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit a transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the power supply of the titanium-aluminum-vanadium alloy target, set the power of the titanium-aluminum-vanadium alloy target to 160 W, and co-sputter for 2 h to deposit an alloy layer on the surface of the transition layer. After the deposition is completed, put it into a heat treatment furnace, heat it to 300 °C at a heating rate of 15 °C / min, hold for 6 h and then cool it. Perform heat treatment for 3 times in the cycle of heating-holding-cooling to obtain the corrosion-resistant steel pipe; Step 3: By mass, add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and ultrasonically disperse for 15 min to form a dispersion with a viscosity of 10 Pa·s. Spray the dispersion onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 Mpa, and the spraying thickness to 100 μm. After the spraying is completed, heat up to 60 °C to completely volatilize the xylene, and finally put it into a heat treatment furnace. Under nitrogen protection, sinter at a sintering temperature of 1300 °C for 4 h. After the sintering is completed, cool it to room temperature with the furnace to obtain the ceramic-coated steel pipe; Step 4: By mass, add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe in the solution and ultrasonically treat for 15 min. After the ultrasonic impregnation is completed, transfer them together to a high-pressure reactor and react at 280 °C and 12 Mpa for 24 h to obtain the wear-resistant stainless steel pipe for pneumatic cylinders.

[0024] Example 2: A preparation process of a wear-resistant stainless steel pipe for pneumatic cylinders is specifically as follows: Step 1: Mix 81.5% stainless steel powder, 0.2% cerium oxide, 3.8% chromium nitride, 4% copper powder, 3% cobalt powder, 1% boron iron powder, and 6.5% tungsten carbide by mass fraction. Use a planetary ball mill to ball mill for 20 min to make them evenly mixed. Then put them into a cylinder mold and press and shape them under a pressure of 750 MPa. After that, put them into a tube furnace and sinter at 1350 - 1400 °C for 2 h under the condition of nitrogen as the protective gas. After sintering, transfer them to a vacuum heat treatment furnace and form a 10 mm thick covering layer on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. Keep them at 1100 °C for 4 h. After heat preservation, cool them to room temperature and temper at 250 °C for 4 h to obtain a cylinder steel pipe; Step 2: After polishing the cylinder steel pipe smoothly, wash it with anhydrous ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder steel pipe in sequence. The process is as follows: First, turn on the power supply and start the vacuum pump to pump the vacuum to 1.5×10 -3 Pa. Then start the heater and heat the cylinder steel pipe to 400 °C at a heating rate of 10 °C / min. Introduce argon into the magnetron sputtering device with a flow rate of 70 sccm, set the bias voltage to -80 V, and perform bias etching for 15 min to remove the oxide layer and pollutants on the cylinder surface. After etching, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit the bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the deposition of the bottom layer is completed, keep other parameters unchanged, introduce nitrogen with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit the transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the power supply of the titanium-aluminum-vanadium alloy target, set the power of the titanium-aluminum-vanadium alloy target to 160 W, and co-sputter for 2 h to deposit the alloy layer on the surface of the transition layer. After deposition, put it into a heat treatment furnace, heat it to 300 °C at a heating rate of 15 °C / min, then keep it warm for 6 h and cool it. Perform heat treatment for 3 times in the cycle of heating - heat preservation - cooling to obtain a corrosion-resistant steel pipe; Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder by mass to xylene, stir evenly, and perform ultrasonic dispersion for 15 min to form a dispersion liquid with a viscosity of 11 Pa·s. Spray the dispersion liquid onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 Mpa, and the spraying thickness to 100 μm. After spraying, heat it to 60 °C to completely volatilize the xylene. Finally, put it into a heat treatment furnace and sinter at a sintering temperature of 1300 °C for 4 h under nitrogen protection. After sintering, cool it to room temperature with the furnace to obtain a ceramic-coated steel pipe; Step 4: By mass parts, add 55 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe into the solution and ultrasonically treat for 15 min. After the ultrasonic impregnation is completed, transfer them together to a high-pressure reactor and react at 280 °C and 12 Mpa for 24 h to obtain a wear-resistant stainless steel pipe for pneumatic cylinders.

[0025] Example 3: A preparation process of a wear-resistant stainless steel pipe for pneumatic cylinders is specifically as follows: Step 1: By mass fraction, mix 81.8% of stainless steel powder, 0.25% of cerium oxide, 3.6% of chromium nitride, 4% of copper powder, 3% of cobalt powder, 0.85% of boron iron powder, and 6.5% of tungsten carbide, and use a planetary ball mill to ball mill for 20 min to make them evenly mixed. Subsequently, put them into a cylinder mold and press and shape them under a pressure of 750 MPa. Then put them into a tube furnace and fire at 1350 - 1400 °C for 2 h under the condition of nitrogen as a protective gas. After the firing is completed, transfer them to a vacuum heat treatment furnace, and use a mixed powder composed of 95% alumina and 5% ammonium chloride to form a 10 mm thick covering layer on the surface, keep warm at 1100 °C for 4 h, cool to room temperature after the heat preservation is completed, and temper at 250 °C for 4 h to obtain a cylinder steel pipe; Step 2: After the cylinder steel pipe is polished smoothly, wash it with absolute ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to sequentially deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power supply, start the vacuum pump to pump the vacuum to 1.5×10 -3 Pa. Subsequently, start the heater and heat the cylinder steel pipe to 400 °C at a heating rate of 10 °C / min. Pass argon into the magnetron sputtering device, with a flow rate of 70 sccm, set the bias voltage to -80 V, and perform bias etching for 15 min to remove the oxide layer and pollutants on the surface of the cylinder. After the etching is completed, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit the bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the deposition of the bottom layer is completed, keep other parameters unchanged, pass nitrogen, with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit the transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the power supply of the titanium-aluminum-vanadium alloy target, set the titanium-aluminum-vanadium alloy target power to 160 W, and co-sputter for 2 h to deposit the alloy layer on the surface of the transition layer. After the deposition is completed, put it into a heat treatment furnace, heat it to 300 °C at a heating rate of 15 °C / min, keep warm for 6 h and then cool, and perform the heat treatment of the cycle of heating - heat preservation - cooling 3 times to obtain a corrosion-resistant steel pipe; Step 3: By mass, add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder into xylene, stir evenly, and disperse ultrasonically for 15 min to form a dispersion with a viscosity of 12 Pa·s. Spray the dispersion onto a corrosion-resistant steel pipe, control the spraying pressure at 0.4 Mpa and the spraying thickness at 100 μm. After spraying, heat up to 60 °C to completely volatilize the xylene. Finally, put it into a heat treatment furnace and sinter at a firing temperature of 1300 °C for 4 h under nitrogen protection. After sintering, cool it to room temperature with the furnace to obtain a ceramic-coated steel pipe; Step 4: By mass, add 60 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea into 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe into the solution and ultrasonically treat for 15 min. After ultrasonic impregnation, transfer them together into a high-pressure reactor and react at 280 °C and 12 Mpa for 24 h to obtain a wear-resistant stainless steel pipe for pneumatic cylinder barrels.

[0026] Based on Example 1 below, control experiments were carried out, specifically Comparative Example 1, Comparative Example 2, and Comparative Example 3, as described below: Comparative Example 1: This comparative example relates to a preparation process of a wear-resistant stainless steel pipe for pneumatic cylinder barrels. The difference from Example 1 is that when processing the cylinder steel pipe by powder metallurgy, the reinforcing phases are only copper powder, cobalt powder, and boron iron powder. Specifically: Step 1: By mass fraction, mix 92% of stainless steel powder, 4% of copper powder, 3% of cobalt powder, and 1% of boron iron powder, ball mill for 20 min using a planetary ball mill to mix evenly, then put it into a cylinder mold and press and shape it at a pressure of 750 MPa. After that, put it into a tubular furnace and sinter at 1350 - 1400 °C for 2 h under the condition of nitrogen as the protective gas. After sintering, transfer it to a vacuum heat treatment furnace, form a 10 mm thick covering layer on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride, keep it warm at 1100 °C for 4 h, cool it to room temperature after heat preservation, and temper at 250 °C for 4 h to obtain a cylinder steel pipe; Step 2: After grinding the cylinder steel pipe smoothly, wash it with absolute ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to sequentially deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder steel pipe. The process is as follows: First, turn on the power supply, start the vacuum pump to pump vacuum to 1.5×10 -3Pa. Subsequently, start the heater and heat the cylinder steel pipe to 400°C at a heating rate of 10°C / min. Introduce argon into the magnetron sputtering device with a flow rate of 70 sccm. Set the bias voltage to -80 V and perform bias etching for 15 min to remove the oxide layer and contaminants on the cylinder surface. After the etching is completed, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit a bottom layer on the corrosion-resistant cylinder steel pipe. After the deposition of the bottom layer is completed, keep other parameters unchanged, introduce nitrogen with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit a transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the power supply of the titanium-aluminum-vanadium alloy target, set the power of the titanium-aluminum-vanadium alloy target to 160 W, and co-sputter for 2 h to deposit an alloy layer on the surface of the transition layer. After the deposition is completed, put it into a heat treatment furnace, heat it to 300°C at a heating rate of 15°C / min, hold for 6 h and then cool it. Perform heat treatment 3 times for the cycle of heating-holding-cooling to obtain a corrosion-resistant steel pipe; Step 3: By mass, add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene, stir evenly, and perform ultrasonic dispersion for 15 min to form a dispersion liquid with a viscosity of 10 Pa·s. Spray the dispersion liquid onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 Mpa, and the spraying thickness to 100 μm. After the spraying is completed, heat it to 60°C to completely volatilize the xylene. Finally, put it into a heat treatment furnace and sinter it at a sintering temperature of 1300°C for 4 h under nitrogen protection. After the sintering is completed, cool it to room temperature with the furnace to obtain a steel pipe with a ceramic coating; Step 4: By mass, add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the steel pipe with a ceramic coating in the solution and perform ultrasonic treatment for 15 min. After the ultrasonic impregnation is completed, transfer them together to a high-pressure reaction kettle and react at 280°C and 12 Mpa for 24 h to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder.

[0027] Comparative Example 2: This comparative example relates to a preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder. The difference from Example 1 is that only a chromium target is used as the metal target during magnetron sputtering deposition, specifically: Step 1: Mix 80.9% stainless steel powder, 0.1% cerium oxide, 4% chromium nitride, 4% copper powder, 3% cobalt powder, 1% boron iron powder, and 7% tungsten carbide by mass fraction. Use a planetary ball mill to ball mill for 20 min to make the mixture uniform. Then put it into a cylinder mold and press and shape it under a pressure of 750 MPa. After that, put it into a tube furnace and sinter at 1350 - 1400 °C for 2 h under the condition of nitrogen as the protective gas. After sintering, transfer it to a vacuum heat treatment furnace and form a 10 mm thick coating layer on the surface with a mixed powder composed of 95% alumina and 5% ammonium chloride. Keep it at 1100 °C for 4 h. After heat preservation, cool it to room temperature and temper at 250 °C for 4 h to obtain a cylinder steel pipe; Step 2: After grinding the cylinder steel pipe flat, wash it with absolute ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder steel pipe in sequence. The process is as follows: First, turn on the power supply and start the vacuum pump to pump the vacuum to 1.5×10 -3 Pa. Then start the heater and heat the cylinder steel pipe to 400 °C at a heating rate of 10 °C / min. Introduce argon into the magnetron sputtering device with a flow rate of 70 sccm, set the bias voltage to -80 V, and perform bias etching for 15 min to remove the oxide layer and contaminants on the cylinder surface. After etching, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit the bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the bottom layer deposition is completed, keep other parameters unchanged, introduce nitrogen with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit the transition layer on the surface of the bottom layer. After the transition layer deposition is completed, set the sputtering time to 2 h to deposit the alloy layer on the surface of the transition layer. After deposition, put it into a heat treatment furnace, heat it to 300 °C at a heating rate of 15 °C / min, keep it warm for 6 h and then cool it. Perform the heat treatment process of cyclic heating - heat preservation - cooling 3 times to obtain a corrosion-resistant steel pipe; Step 3: Add 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder to xylene by mass. Stir evenly and ultrasonically disperse for 15 min to form a dispersion liquid with a viscosity of 10 Pa·s. Spray the dispersion liquid onto the corrosion-resistant steel pipe, control the spraying pressure to 0.4 Mpa, and the spraying thickness to 100 μm. After spraying, heat up to 60 °C to completely volatilize the xylene. Finally, put it into a heat treatment furnace and sinter at a sintering temperature of 1300 °C for 4 h under nitrogen protection. After sintering, cool it to room temperature with the furnace to obtain a ceramic-coated steel pipe; Step 4: By mass, add 50 parts of D-glucose, 8.8 parts of sodium molybdate, and 13 parts of thiourea to 200 parts of deionized water, stir evenly, and fully dissolve to obtain a mixed solution. Subsequently, immerse the ceramic-coated steel pipe into the solution and ultrasonicate for 15 min. After the ultrasonic impregnation is completed, transfer them together to a high-pressure reactor and react at 280 °C and 12 Mpa for 24 h to obtain a wear-resistant stainless steel pipe for pneumatic cylinder barrels.

[0028] Comparative Example 3: This comparative example relates to a preparation process of a wear-resistant stainless steel pipe for pneumatic cylinder barrels. The difference from Example 1 is that the mixed solution of D-glucose, sodium molybdate, and thiourea is not impregnated. Specifically: Step 1: By mass fraction, mix 80.9% of stainless steel powder, 0.1% of cerium oxide, 4% of chromium nitride, 4% of copper powder, 3% of cobalt powder, 1% of boron iron powder, and 7% of tungsten carbide, and use a planetary ball mill to ball mill for 20 min to make the mixture uniform. Subsequently, put it into a cylinder mold and press and shape it under a pressure of 750 MPa. Then put it into a tube furnace and fire it at 1350 - 1400 °C for 2 h under the condition of nitrogen as a protective gas. After firing is completed, transfer it to a vacuum heat treatment furnace, and use a mixed powder composed of 95% alumina and 5% ammonium chloride to form a 10 mm thick covering layer on the surface, keep it at 1100 °C for 4 h, cool to room temperature after heat preservation is completed, and temper at 250 °C for 4 h to obtain a cylinder steel pipe; Step 2: After the cylinder steel pipe is polished flat, wash it with absolute ethanol and deionized water, dry it at 80 °C, and then use magnetron sputtering technology to deposit a 0.2 μm thick bottom layer, a 0.1 μm thick transition layer, and a 0.23 μm thick alloy layer on the surface of the cylinder steel pipe in sequence. The process is as follows: First, turn on the power supply, start the vacuum pump to pump the vacuum to 1.5×10 -3 Pa, then start the heater, heat the cylinder steel pipe to 400 °C at a heating rate of 10 °C / min, introduce argon into the magnetron sputtering device, with a flow rate of 70 sccm, set the bias voltage to -80 V, and perform bias etching for 15 min to remove the oxide layer and pollutants on the surface of the cylinder. After etching is completed, set the argon flow rate to 30 sccm, the sputtering pressure to 0.42 Pa, the chromium target power to 200 W, and the magnetron sputtering time to 10 min to deposit the bottom layer on the surface of the corrosion-resistant cylinder steel pipe. After the bottom layer deposition is completed, keep other parameters unchanged, introduce nitrogen, with a nitrogen flow rate of 10 sccm, and perform magnetron sputtering for 10 min to deposit the transition layer on the surface of the bottom layer. After the transition layer deposition is completed, turn on the power supply of the titanium-aluminum-vanadium alloy target, set the titanium-aluminum-vanadium alloy target power to 160 W, and co-sputter for 2 h to deposit the alloy layer on the surface of the transition layer. After deposition is completed, put it into a heat treatment furnace, heat it to 300 °C at a heating rate of 15 °C / min, keep it warm for 6 h and then cool it, and perform the heat treatment of the cycle of heating - heat preservation - cooling 3 times to obtain a corrosion-resistant steel pipe; Step 3: Weigh 10 parts of polysilazane, 5 parts of silicon nitride powder, and 1.5 parts of ytterbium oxide powder by mass, add them to xylene, stir evenly, and disperse ultrasonically for 15 min to form a dispersion with a viscosity of 10 Pa·s. Spray the dispersion onto a corrosion-resistant steel pipe, control the spraying pressure at 0.4 Mpa and the spraying thickness at 100 μm. After spraying, heat up to 60 °C to completely volatilize the xylene. Finally, put it into a heat treatment furnace and sinter at a firing temperature of 1300 °C for 4 h under nitrogen protection. After sintering, cool it to room temperature with the furnace to obtain a wear-resistant stainless steel pipe for pneumatic cylinder barrels.

[0029] Detection experiment: According to the preparation processes of the wear-resistant stainless steel pipes for pneumatic cylinder barrels in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, and Comparative Example 3 respectively, process steel plates of the same material to prepare a batch of wear-resistant stainless steel plate samples, and conduct adhesion tests, microhardness tests, friction and wear performance tests, and corrosion resistance tests.

[0030] Adhesion test: The adhesion test of the coating on the sample surface is based on "Review of Test Methods for Adhesion of Metallic Coatings on Metallic Substrates - Electrodeposited and Chemically Deposited Coatings" (GB / T 5270-2024). Use a UMT-3 comprehensive mechanical property testing machine for testing. After fixing the sample with a fixture, press a conical diamond indenter with a tip radius of 0.2 mm on the coating surface. Set the initial load at 0 N, the load acceleration at 10 N / min, and the scratch speed at 5 mm / min until the coating peels off. Record the critical load of the sample. Select 3 different positions on each sample for measurement, and take the average value of the results.

[0031] Microhardness test: The microhardness test of the sample is based on "Metallic Materials - Vickers and Knoop Microhardness Tests for Metallic and Other Inorganic Coatings" (GB / T 9790-2020). Use an HSV-1000 digital display microhardness tester (Sivaka Precision Measuring Instrument) and a Knoop indenter. After fixing the sample with a fixture, move the fixture to align the center of the indenter with the area to be measured on the sample. Set the load at 100 gf and the application time at 10 s. Select 5 points for testing on each sample, and take the average value of the results.

[0032] Friction and wear performance test: The friction and wear performance test is carried out using an HSR-2M reciprocating friction and wear testing machine (Zhongke Kaihua). The size of the sample is 10 mm × 10 mm × 10 mm. After fixing the sample with a fixture, use the coated side of the sample to rub against the counter-material. The counter-material is a GCr15 high-carbon chromium bearing steel ball with a diameter of 4 mm. The load is 500 g, the sliding stroke is 5 mm, the friction time is 15 min, and the ambient temperature is 25 °C. After the friction, observe the wear morphology of the sample with a scanning electron microscope and calculate the wear rate of the sample.

[0033] Corrosion resistance test: The corrosion resistance test was carried out in accordance with "Artificial Atmosphere Corrosion Test - Salt Spray Test" (GB / T 10125-2012). A neutral salt spray test chamber was used for the test. After weighing the samples, they were placed in the test chamber. The angle of the samples was adjusted to 25° with respect to the vertical direction, and the coated side was used as the effective test surface. The non-test areas were covered with adhesive tape. The corrosion solution was a 5% by mass sodium chloride solution. The temperature in the salt spray chamber was 35°C. After 48 h, the samples were taken out of the test chamber, immersed in a 20% by mass diammonium citrate solution for 10 min, taken out after 10 min, and the surface was washed with ethanol and deionized water. After drying at 60°C, the samples were weighed, and the mass loss of the samples was calculated.

[0034]

[0035] Conclusion: From the test results of each test, it can be seen that the adhesion, microhardness, wear rate, and corrosion mass loss of the wear-resistant stainless steel plate samples processed by the preparation processes of each embodiment are better than those of the comparative example. The preparation process of the wear-resistant stainless steel pipe for pneumatic cylinder barrels provided by the present invention can process stainless steel pipes with good hardness, wear resistance, and corrosion resistance. The wear-resistant and corrosion-resistant coating on the steel pipe is tightly combined and not easy to fall off, can meet complex and harsh working conditions, has a long service life, and reduces the number of times of damage and the replacement frequency of the cylinder barrel during use.

[0036] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, in any regard, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be embraced within the present invention.

Claims

1. A preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel, characterized in that: Specifically: Step 1: After evenly ball-milling and mixing stainless steel powder with the reinforcing phase, place it into a cylinder mold and press-mold it under a pressure of 700 - 800 MPa. Subsequently, under nitrogen protection, heat it to 1350 - 1400 °C and sinter for 1 - 3 h. After sintering, through heat treatment and tempering processes, a cylinder steel pipe is obtained; Step 2: After grinding the cylinder steel pipe smoothly, wash it with anhydrous ethanol and deionized water, dry it at 80 °C, and then, using magnetron sputtering technology, sequentially deposit a bottom layer, a transition layer, and an alloy layer on the surface of the cylinder steel pipe to obtain a corrosion-resistant steel pipe; Step 3: Disperse polysilazane, silicon nitride, and ytterbium oxide into xylene to form a dispersion liquid. Subsequently, spray the dispersion liquid onto the corrosion-resistant steel pipe. After spraying, heat it to 50 - 70 °C to completely volatilize the xylene, and then sinter it at 1250 - 1300 °C for 3 - 5 h under nitrogen protection. After sintering, cool it to room temperature to obtain a ceramic-coated steel pipe; Step 4: Dissolve D-glucose, sodium molybdate, and thiourea into deionized water to form a lubricating coating solution. Finally, immerse the ceramic-coated steel pipe into the lubricating coating solution and ultrasonicate for 10 - 20 min. After impregnation, react the ceramic-coated steel pipe together with the lubricating coating solution at 270 - 300 °C and 10 - 15 MPa for 24 h to obtain a wear-resistant stainless steel pipe for a pneumatic cylinder; 2. The preparation process of a wear-resistant stainless steel tube for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 1, the reinforcing phase consists of cerium oxide, chromium nitride, copper powder, cobalt powder, boron iron powder, and tungsten carbide; in the cylinder steel pipe, the mass fraction of cerium oxide is 0.05% - 0.3%, the mass fraction of chromium nitride is 3.4% - 3.8%, the mass fraction of copper powder is 3% - 5%, the mass fraction of cobalt powder is 2% - 4%, the mass fraction of boron iron powder is 0.8% - 1.2%, the mass fraction of tungsten carbide is 6% - 8%, and the balance is stainless steel powder; 3. The preparation process of a wear-resistant stainless steel tube for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 1, the heat treatment and tempering processes are specifically as follows: Mix alumina and ammonium chloride in a mass ratio of (93 - 97):(3 - 7), cover it on the surface of the sintered product with a thickness of 5 - 10 mm, keep it at 1100 - 1150 °C for 4 h, cool it to room temperature after insulation, and temper it at 250 - 300 °C for 3 - 5 h to obtain a cylinder steel pipe; 4. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 2, the thickness of the bottom layer is 0.1 - 0.3 μm, the thickness of the transition layer is 0.05 - 0.1 μm, and the thickness of the alloy layer is 0.18 - 0.28 μm; 5. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 2, the specific process of magnetron sputtering is as follows: First, turn on the power supply and start the vacuum pump to pump the vacuum to 1.2×10 -3 -1.5×10 -3 Pa. Subsequently, start the heater and heat the cylinder steel tube to 380 - 400 °C at a heating rate of 6 - 10 °C / min. Then, introduce argon into the magnetron sputtering device with a flow rate of 70 - 80 sccm. Set the bias voltage to (-60) - (-80) V and perform bias etching for 10 - 20 min. After the etching is completed, turn on the chromium target power supply to deposit a bottom layer on the surface of the corrosion-resistant cylinder steel tube. After the deposition of the bottom layer is completed, introduce nitrogen to deposit a transition layer on the surface of the bottom layer. After the deposition of the transition layer is completed, turn on the titanium-aluminum-vanadium alloy target power supply to deposit an alloy layer on the surface of the transition layer.

6. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 5, characterized in that: During magnetron sputtering, the argon gas flow rate is 30 - 40 sccm, the sputtering pressure is 0.4 - 0.5 Pa, the power of the chromium target is 180 - 200 W, and the sputtering deposition time of the bottom layer is 10 - 15 min; the nitrogen gas flow rate is 10 - 20 sccm, and the sputtering deposition time of the transition layer is 5 - 10 min; the power of the titanium-aluminum-vanadium alloy target is 150 - 180 W, and the sputtering deposition time of the alloy layer is 2 - 3 h; 7. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 2, heat treatment is carried out after magnetron sputtering. Specifically: After deposition, heat it to 280 - 300 °C at a heating rate of 10 - 15 °C / min, keep it warm for 5 - 6 h and then cool it. Repeat the heating-holding-cooling process for heat treatment 3 - 5 times to obtain a corrosion-resistant steel pipe.

8. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 3, the mass ratio of polysilazane, silicon nitride powder, and ytterbium oxide powder is (8 - 12):(4 - 6):(1 - 2); the viscosity of the dispersion liquid is 8 - 12 Pa·s.

9. The preparation process of a wear-resistant stainless steel pipe for a pneumatic cylinder barrel according to claim 1, characterized in that: In Step 4, the mass ratio of D-glucose, sodium molybdate, thiourea, and deionized water is (50 - 60):(8 - 10):(10 - 15):(180 - 220).

10. A wear-resistant stainless steel pipe for a pneumatic cylinder barrel, which is processed by using the preparation process described in any one of Claims 1 - 9.

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